ab.exe介绍
ab.exe是apache server的一个组件，用于监测并发请求，并显示监测数据
具体使用及下载地址请参考：http://www.cnblogs.com/gossip/p/4398784.html
本文的目的
通过webapi接口模拟100个并发请求下，同步和异步访问数据库的性能差异
创建数据库及数据
--创建表结构
CREATE TABLE dbo.[Cars] (
Id INT IDENTITY(1000,1) NOT NULL,
Model NVARCHAR(50) NULL,
Make NVARCHAR(50) NULL,
[Year] INT NOT NULL,
Price REAL NOT NULL,
CONSTRAINT [PK_Cars] PRIMARY KEY CLUSTERED (Id) ON [PRIMARY]
) ON [PRIMARY];
GO
--创建存储过程
CREATE PROCEDURE [dbo].[sp$GetCars]
AS
-- 存储过程执行过程中等待一秒
WAITFOR DELAY '00:00:01';
SELECT * FROM Cars;
GO
--初始化数据
INSERT INTO dbo.Cars VALUES('Car1', 'Model1', 2006, 24950);
INSERT INTO dbo.Cars VALUES('Car2', 'Model1', 2003, 56829);
INSERT INTO dbo.Cars VALUES('Car3', 'Model2', 2006, 17382);
INSERT INTO dbo.Cars VALUES('Car4', 'Model3', 2002, 72733);
编写webapi程序
1、数据访问类（包含同步/异步访问数据库的方法）
public class GalleryContext
{
readonly string _spName = "sp$GetCars";
readonly string _connectionString =
ConfigurationManager.ConnectionStrings["TestDBConnStr"].ConnectionString;
/// <summary>
/// 同步获取数据
/// </summary>
/// <returns></returns>
public IEnumerable<Car> GetCarsViaSP()
{
using (var conn = new SqlConnection(_connectionString))
{
using (var cmd = new SqlCommand())
{
cmd.Connection = conn;
cmd.CommandText = _spName;
cmd.CommandType = CommandType.StoredProcedure;
conn.Open();
using (var reader = cmd.ExecuteReader())
{
return reader.Select(r => carBuilder(r)).ToList();
}
}
}
}
/// <summary>
/// 异步获取数据
/// </summary>
/// <returns></returns>
public async Task<IEnumerable<Car>> GetCarsViaSPAsync()
{
using (var conn = new SqlConnection(_connectionString))
{
using (var cmd = new SqlCommand())
{
cmd.Connection = conn;
cmd.CommandText = _spName;
cmd.CommandType = CommandType.StoredProcedure;
conn.Open();
using (var reader = await cmd.ExecuteReaderAsync()) //调用异步方法
{
return reader.Select(r => carBuilder(r)).ToList();
}
}
}
}
//private helpers
private Car carBuilder(SqlDataReader reader)
{
return new Car
{
Id = int.Parse(reader["Id"].ToString()),
Make = reader["Make"] is DBNull ? null : reader["Make"].ToString(),
Model = reader["Model"] is DBNull ? null : reader["Model"].ToString(),
Year = int.Parse(reader["Year"].ToString()),
Price = float.Parse(reader["Price"].ToString()),
};
}
}
2、数据库对应实体类及辅助扩展方法
public class Car
{
public int Id { get; set; }
public string Make { get; set; }
public string Model { get; set; }
public int Year { get; set; }
public float Price { get; set; }
}
public static class Extensions
{
public static IEnumerable<T> Select<T>(
this SqlDataReader reader, Func<SqlDataReader, T> projection)
{
while (reader.Read())
{
yield return projection(reader);
}
}
}
3、webapi Controller调用方法
//同步调用接口
public class SPCarsSyncController : ApiController
{
readonly GalleryContext galleryContext = new GalleryContext();
public IEnumerable<Car> Get()
{
return galleryContext.GetCarsViaSP();
}
}
//异步调用接口
public class SPCarsAsyncController : ApiController
{
readonly GalleryContext galleryContext = new GalleryContext();
public async Task<IEnumerable<Car>> Get()
{
return await galleryContext.GetCarsViaSPAsync();
}
}
4、数据库连接配置文件
<connectionStrings>
<add name="TestDBConnStr"
connectionString="Server=你的数据库地址;Database=TestDB;User Id=sa;Password=123;Integrated Security=false;Max Pool Size=500;Asynchronous Processing=True;"
providerName="System.Data.SqlClient" />
</connectionStrings>
其中：
Max Pool Size：表示连接池的最大数量
Asynchronous Processing=True;表示数据库支持异步处理
Integrated Security=false;此处设为true或不设置会抛出异常
Login failed for user 'NT AUTHORITY\SYSTEM'
使用ab.exe模拟并发请求
模拟请求同步服务：
模拟请求异步服务：
结论：
访问相同的数据表及数据，
使用同步方式共用时20秒，平均每秒处理5个请求；
使用异步方式共用时10秒，平均每秒处理10个请求；